calcitriol and Uterine-Neoplasms

Early pregnancy is characterised by elevated circulating levels of vitamin D binding protein (DBP). The impact of this on maternal and fetal health is unclear but DBP is present in the placenta, and DBP gene variants have been linked to malplacentation disorders such as preeclampsia. The functional role of DBP in the placenta was investigated using trophoblastic JEG3, BeWo and HTR8 cells. All three cell lines showed intracellular DBP with increased expression and nuclear localisation of DBP in cells treated with the active form of vitamin D, 1,25-dihydroxyvitamin D (1,25D). When cultured in the serum of mice lacking DBP (DBP-/-), JEG3 cells showed no intracellular DBP indicating uptake of exogenous DBP. Inhibition of the membrane receptor for DBP, megalin, also suppressed intracellular DBP. Elimination of intracellular DBP with DBP-/- serum or megalin inhibitor suppressed matrix invasion by trophoblast cells and was associated with increased nuclear accumulation of G-actin. Conversely, treatment with 1,25D enhanced matrix invasion. This was independent of the nuclear vitamin D receptor but was associated with enhanced ERK phosphorylation, and inhibition of ERK kinase suppressed trophoblast matrix invasion. When cultured with serum from pregnant women, trophoblast matrix invasion correlated with DBP concentration, and DBP was lower in first-trimester serum from women who later developed preeclampsia. These data show that the trophoblast matrix invasion involves uptake of serum DBP and associated intracellular actin-binding and homeostasis. DBP is a potential marker of placentation disorders such as preeclampsia and may also provide a therapeutic option for improved placenta and pregnancy health.

Topics: Actins; Cell Line; Cell Line, Tumor; Cell Nucleus; Choriocarcinoma; Extracellular Signal-Regulated MAP Kinases; Female; Gene Knockdown Techniques; Humans; Phosphorylation; Placentation; Pre-Eclampsia; Pregnancy; Receptors, Calcitriol; Trophoblasts; Uterine Neoplasms; Vitamin D; Vitamin D-Binding Protein

Uterine fibroids (UFs) are the most common benign tumors in premenopausal women. In this study, we evaluated the effects of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] for the treatment of UFs.. To determine the role of 1,25(OH)2D3 on the expression of sex steroid receptors in human UF cells.. Human UFs and their adjacent myometrium were analyzed for expression of estrogen receptor (ER)-α, progesterone receptor (PR)-A, and PR-B, as well as members of the steroid receptor coactivator (SRC) family. Immortalized human uterine fibroid (human uterine leiomyoma [HuLM]) cells were treated with 1,25(OH)2D3 and assayed for the expression and localization of the aforementioned receptors and SRCs using Western blot, immunohistochemistry, immunofluorescence, and immunoprecipitation assays.. We discovered a correlation between reduced levels of vitamin D receptor (VDR) and increased levels of ER-α, PR-A, and PR-B in these tissues. We evaluated the effects of 1,25(OH)2D3 on the regulation of the aforementioned sex steroid receptors.. We observed an inverse correlation between the up-regulated ER-α, PR-A, and PR-B and expression of VDR in UFs. Treatment with 1,25(OH)2D3 significantly decreased levels of ER-α, PR-A, and PR-B, as well as SRCs in HuLM cells (P < .05). In contrast, 1,25(OH)2D3 self-induced its own VDR, which resulted in an induction of VDR-retinoid X receptor-α complex in HuLM cells. Together, these results suggest that 1,25(OH)2D3 functions as an antagonist of sex steroid hormone receptors in HuLM cells.. 1,25(OH)2D3 functions as a potent antiestrogenic/antiprogesteronic agent that may have utility as a novel therapeutic option for UF.

Topics: Cell Proliferation; Estrogen Receptor alpha; Female; Humans; Leiomyoma; Myometrium; Receptors, Calcitriol; Receptors, Progesterone; Tumor Cells, Cultured; Uterine Neoplasms; Vitamin D

We examined the antitumor and therapeutic potentials of paricalcitol, an analog of 1,25-dihydroxyvitamin D3 with lower calcemic activity, against uterine fibroids using in vitro and in vivo evaluations in appropriate uterine fibroid cells and animal models. We found that paricalcitol has potential to reduce the proliferation of the immortalized human uterine fibroid cells. For the in vivo study, we generated subcutaneous tumors by injecting the Eker rat-derived uterine leiomyoma cell line (ELT-3) rat uterine fibroid-derived cell line in athymic nude mice supplemented with estrogen pellets. These mice were administered with vehicle versus paricalcitol (300 ng/kg/d) or 1,25-dihydroxyvitamin D3 (500 ng/kg/d) for 4 consecutive weeks, and the data were analyzed. We found that while both paricalcitol and 1,25-dihydroxyvitamin D3 significantly reduced fibroid tumor size, the shrinkage was slightly higher in the paricalcitol-treated group. Together, our results suggest that paricalcitol may be a potential candidate for effective, safe, and noninvasive medical treatment option for uterine fibroids.

Topics: Animals; Antineoplastic Agents; Cell Line, Transformed; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Dose-Response Relationship, Drug; Ergocalciferols; Female; Humans; Leiomyoma; Mice; Mice, Nude; Random Allocation; Rats; Receptors, Calcitriol; Uterine Neoplasms; Vitamin D

Uterine fibroids (leiomyomas) are the most common benign tumors associated with excessive deposition of extracellular matrix (ECM)-associated proteins that increase fibroid tumorigenicity. Herein, we determined the expression levels of vitamin D receptor (VDR) protein in human uterine fibroids and compared these levels to those in adjacent normal myometrium. Using Western blot analysis, we found that more than 60% of uterine fibroids analyzed (25 of 40) expressed low levels of VDR. We also found that the biologically active 1,25-dihydroxyvitamin D3 (1,25[OH]2D3), which functions via binding to its nuclear VDR, induced VDR in a concentration-dependent manner and reduced ECM-associated fibrotic and proteoglycans expression in immortalized human uterine fibroid cell line (HuLM). At 1-10 nM concentrations, 1,25(OH)2D3 significantly induced (P < 0.05) nuclear VDR, which was further stimulated by higher concentrations of 1,25(OH)2D3 in HuLM cells. 1,25(OH)2D3 at 10 nM also significantly reduced (P < 0.05) the protein expression of ECM-associated collagen type 1, fibronectin, and plasminogen activator inhibitor-1 (PAI-1) in HuLM cells. We also found that 1,25(OH)2D3 reduced mRNA and protein expressions of proteoglycans such as fibromodulin, biglycan, and versican in HuLM cells. Moreover, the aberrant expression of structural smooth muscle actin fibers was reduced by 1,25(OH)2D3 treatment in a concentration-dependent manner in HuLM cells. Taken together, our results suggest that human uterine fibroids express reduced levels of VDR compared to the adjacent normal myometrium and that treatment with 1,25(OH)2D3 can potentially reduce the aberrant expression of major ECM-associated proteins in HuLM cells. Thus, 1,25(OH)2D3 might be an effective, safe, nonsurgical treatment option for human uterine fibroids.

Topics: Adult; Cells, Cultured; Down-Regulation; Extracellular Matrix; Extracellular Matrix Proteins; Female; Gene Expression Regulation, Neoplastic; Humans; Leiomyoma; Middle Aged; Myocytes, Smooth Muscle; Receptors, Calcitriol; Uterine Neoplasms; Uterus; Vitamin D